Micro Electro-Mechanical Systems (MEMS), such as motion sensors, inertial sensors, and movable mirrors, are being widely used. As is well known, a MEMS motion sensor may be, for example, an accelerometer for detecting linear motion, or a gyroscope for detecting rotation and angular velocities.
Advanced planar silicon manufacturing processes have become the main manufacturing techniques in MEMS. Direct bonding of double or triple silicon wafers has been recognized as the most attractive packaging technology. However, integrated and robust wafer bonding involving multiple wafers in manufacturing a MEMS device remains a challenge.